textproduct: Quad Cities

KEY MESSAGES

- Seasonable temperatures and more comfortable humidity return today and will last through much of the week.

- The next round of rain appears likely (50-70%) Thursday night through Friday with widespread showers and storms.

- Wildfire smoke aloft will remain over the area for the next several days. While near-surface concentrations are expected to be low, hazy skies are likely.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 154 AM CDT Tue Jul 28 2026

With the cold front now through the area, temperatures and dewpoints early this morning have settled into the mid 70s to low 80s and low to upper 70s, respectively. This will lead to much more seasonable temperatures and more comfortable humidity today as high pressure slides into the Great Lakes region. Highs today will be in the mid to upper 80s, with northeast Missouri having a low chance (10-20%) of reaching into the low 90s. With this drop in temperatures from yesterday, the lower humidity will be quite apparent as heat indices reach only into the upper 80s to mid 90s. Also apparent will be the presence of wildfire smoke aloft. This smoke will stay mostly aloft due to the lack of deep vertical mixing. It is possible that, if thick enough, this layer of smoke aloft could help temper highs by a degree or two.

A similar story repeats on Wednesday as we remain under the influence of high pressure over the Great Lakes. Highs once again will be in the mid to upper 80s as clear skies allow for strong diurnal heating. By Wednesday afternoon, smoke aloft will disperse slightly before another wave of smoke aloft moves in overnight into Thursday.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 154 AM CDT Tue Jul 28 2026

Thursday... Once again, Thursday will continue the trend of calm and seasonable summer days, albeit with some differences. The most notable of these is the combination of the ridge retrograding westward and a shortwave translating through its northern periphery in the Great Plains. Locally, southerly to southeasterly low-level flow around the high pressure to our east will advect in a moister airmass. Together, this will set the stage for our next round of showers and storms Thursday night and Friday.

Thursday Night through Friday... As previously mentioned, a combination of the upper level ridge retrograding and a shortwave trough will lead to weakening in the ridge through the Great Plains into the Great Lakes region. As this shortwave translates through the northeast edge of the ridge, it will provide lift across the area. This will result in the potential for showers and potentially a few thunderstorms.

With any chances for thunderstorms comes the question of how likely severe thunderstorms are. Environmental parameters suggest that severe storms have a lower probability (10-20%), as deep layer shear of 10-30 kts and MUCAPE of less than 1000 J/kg would provide only a marginal degree of support for any organized convection. However, parameters upstream in the Great Plains are better aligned to support organized convection, suggesting there could be potential for organized storms to form in this area. Additional uncertainty is in the timing of this system, as guidance differs on how long the trough will take to move through the region, One example is the deterministic ECMWF, which has the system linger into the weekend and would thus have a longer period of rainfall. We will continue to monitor this system in the coming days.

Saturday through Monday... Following the passage of the shortwave, upper level flow will become northerly as an area of high pressure sets up over the northern Great Lakes. This will result in cooler temperatures as we enter the weekend, with the potential for highs in the upper 70s to low 80s Saturday. Over the course of the weekend, subtle ridging and low-level warm advection will bring temperatures up into the 80s once more.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1217 AM CDT Tue Jul 28 2026

VFR conditions are expected for the duration of the TAF period. METAR observations show that the cold front has passed through all terminals, turning winds northwesterly to northerly. With incoming mid and high clouds, radiational cooling should slow enough to limit any patchy areas of fog through this morning. While there will be high concentrations of smoke aloft, it is unlikely that this smoke will mix down to the surface and limit visibility.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.